SciClone Announces Additional Topline Results for SCV-07

Company Establishes Scientific Advisory Board for SCV-07 in Oral
Mucositis

FOSTER CITY, CA – May 17, 2010 – SciClone
Pharmaceuticals, Inc. (NASDAQ: SCLN) today announced further
topline results from the company’s phase 2 proof of concept
study of SCV-07 for the prevention of severe oral mucositis (OM;
WHO grades 3-4) in patients with advanced head and neck cancer -- a
painful and debilitating condition caused by chemoradiotherapy
regimens.

High dose SCV-07 The incidence of severe OM after 5 weeks of
chemoradiation was 30% lower in the patients in the high dose
treatment arm (0.1 mg/kg; 17 patients) compared to the 20 patients
who received placebo (29% vs. 42%). A post hoc data analysis of
ulcerative mucositis (WHO grades 2- 4), a major cause of morbidity
associated with OM, was also conducted. The high dose of SCV-07
prevented the onset of any ulcerative mucositis in 24% of patients
at doses of radiation up to 50Gy (after approximately 5 weeks of
treatment) while 100% of patients in the placebo group suffered
from ulcerative mucositis at 35Gy (after approximately 3.5 weeks of
treatment).

Supportive of these findings, the high dose SCV-07 group also
showed improvement over placebo for exploratory endpoints,
including the use of gastric tube feedings, unplanned office or
emergency room visits, and breaks in planned course of radiation
therapy of one week or longer.

Low dose SCV-07 The incidence of severe OM after 5 weeks of
chemoradiation was 50% higher in the patients in the low-dose
treatment arm (0.02 mg/kg; 20 patients) compared to the 20 patients
who received placebo (63% vs. 42%). However, the post hoc data
analysis of ulcerative mucositis showed that the low dose of SCV-07
prevented the onset of any ulcerative mucositis in 5% of patients
at doses of radiation up to 50Gy compared to 100% of patients in
the placebo group who suffered from ulcerative mucositis at
35Gy.

Regarding exploratory endpoints, the low dose group showed
similar results to the placebo group.

These results suggest that SCV-07 may be acting on different
biological pathways at different doses.

Safety Importantly, both doses of SCV-07 were shown to be safe
and well tolerated, with no SCV-07-related serious adverse events
reported in either dose arm. The distribution and incidence of
adverse events was similar between SCV-07- and placebo-treated
patients. The most frequent adverse events in all patients were
gastrointestinal disorders (such as nausea and dry mouth), general
disorders (such as fatigue and fever), and local injection site
reactions. This safety profile supports the potential to administer
higher doses of SCV-07 in future clinical studies evaluating oral
mucositis.

The initial findings were previously reported by SciClone on
March 30, 2010.

Scientific Advisory Board SciClone recently formed a scientific
advisory board (SAB) to provide guidance and oversight for the
company’s ongoing clinical development of SCV-07 for this
indication. The newly established SAB, which includes medical and
radiation oncology thought leaders, is working with SciClone to
design the clinical development strategy for the OM program based
on findings from this study.

“SAB members were encouraged by the findings from
SciClone’s phase 2 proof of concept study which suggested a
consistent trend favoring patients in the trial’s high dose
group,” said Dr. Stephen T. Sonis, Chief of the Division of
Oral Medicine at the Dana-Farber Cancer Institute; Senior Surgeon
at Brigham and Women’s Hospital; Clinical Professor of Oral
Medicine at Harvard. “Furthermore, the data from the study
offered insight into study design for the next phase 2
trial.”

SciClone’s newly established SAB includes the following
thought leaders from the oncology community:

“Through this newly formed SAB, we believe that we have
assembled a team of key opinion leaders in the area of oral
mucositis. We are grateful that these experts have agreed to
provide their guidance to this important program - a program that
we hope will ultimately offer patients and physicians a solution to
a significant unmet medical need,” commented Friedhelm
Blobel, Ph.D., SciClone’s President and Chief Executive
Officer. “We appreciate the efforts already put forth by this
Board in assisting the ongoing clinical development of SCV-07 for
OM and look forward to the important contributions that they will
make as we continue to advance the program.”

Topline details of the SCV-07 OM clinical development strategy
include:

· Plans to conduct another trial to confirm the efficacy
of the 0.10 mg/kg SCV-07 dose and to explore two additional, higher
dose levels, as a result of the clinically meaningful signal in
delaying the onset of OM seen in patients treated with the 0.10
mg/kg SCV-07 dose;

· Meeting with the United States Food and Drug
Administration (FDA) in the second quarter of 2010 to discuss the
results of this phase 2 proof of concept study and plans for the
new phase 2 study;

· If a positive FDA response is received including FDA
agreement on the overall design of the study, SciClone would
initiate the new phase 2 study promptly.

About Oral Mucositis OM is a common, painful, debilitating
complication of cancer treatment, and SciClone estimates that total
medical costs may reach around $4.2 billion in the U.S. and $10
billion worldwide in 2010. OM is a condition in which the sensitive
cells lining the mouth and throat are damaged by cancer treatments
such as chemotherapy (with or without radiation) and become painful
mouth sores. Severe OM has been reported to occur in about 50% of
patients who receive chemoradiation for the prevention of cancers
of head and neck (Sonis, Core Evidence, 2009). Importantly,
radiation to the head and neck, especially when it includes the
tissues of the mouth, pharynx and hypopharynx, results in
significant ulcerative OM in greater than 90% of patients (Manas et
al, Clinical Translational Oncology, 2009) and can compromise the
patient’s ability or willingness to accept a complete course
of therapy. Symptoms can include painful ulcers in the mouth and
throat, redness and swelling of the gums, dryness and overall
soreness in the mouth, and difficulty eating, swallowing, talking
and drinking. In addition to the symptoms of OM and its impact on
quality of life and continued therapy, mucositis can cause adverse
affects on a variety of other health and economic outcomes, such as
a risk of serious infection, the need for parenteral nutrition and
narcotic analgesia, and increased hospitalization and feeding-tube
placement. The National Cancer Institute estimates that 400,000
patients in the U.S. suffer from OM during cancer therapy.

About SciClone

SciClone Pharmaceuticals (NASDAQ: SCLN) is a profit-focused,
global specialty pharmaceutical company with a substantial
international business and a product portfolio of novel therapies
for cancer and infectious diseases. SciClone is focused on
continuing international sales growth, a cost-containing clinical
development strategy, and overall expense management. ZADAXIN®
(thymalfasin or thymosin alpha 1) is sold in over 30 countries for
the treatment of hepatitis B (HBV) and hepatitis C (HCV), certain
cancers and as a vaccine adjuvant. SciClone’s pipeline of
drug candidates includes thymalfasin, in clinical studies as an
enhancer of vaccines; SCV-07 in a phase 2 trial for the delay to
onset of severe oral mucositis in patients receiving chemoradiation
therapy for the treatment of cancers of the head and neck; and
SCV-07 in a phase 2 trial for the treatment of HCV. SciClone has
exclusive commercialization and distribution rights to DC BeadTM in
China, where the product is under regulatory review. The Company
also has exclusive commercialization and distribution rights to the
anti-nausea drug ondansetron RapidFilmTM in China, including Hong
Kong and Macau, and Vietnam, for which it will seek regulatory
approval. For additional information, please visit
Hwww.sciclone.comwww.sciclone.com>H.

Forward-Looking Statements This press release contains
forward-looking statements regarding development objectives and
timing expectations. You are urged to consider statements that
include the words "may," "will," "would," "could," "should,"
"might," "believes," "estimates," "projects," "potential,"
"expects," "potential," "plans," "anticipates," "intends,"
"continues," "forecast," "designed," "goal," or the negative of
those words or other comparable words to be uncertain and
forward-looking. These statements are subject to risks and
uncertainties that are difficult to predict and actual outcomes may
differ materially. These risks and uncertainties include the
outcome of our discussions with the FDA and whether we are able to
initiate the Phase 2 trial., and if commenced, complete clinical
trials of SCV-07 and for such trials to demonstrate SCV-07 having a
significant therapeutic effect for treatment of OM without adverse
side effects. Please also refer to other risks and uncertainties
described in SciClone's filings with the SEC. All forward-looking
statements are based on information currently available to SciClone
and SciClone assumes no obligation to update any such
forward-looking statements.